The Hudson River is in New York state, in the United States.
The river is about 507 kilometers (315 miles) long.
It flows almost entirely within New York state – the exception being its final segment, where it forms the boundary between New York and New Jersey for 34 km (21 miles).
The source of the Hudson River is Lake Tear of the Clouds in the Adirondack Park at an altitude of 1,317 meters (4,322 feet). The river flows through the Hudson Valley to the Upper New York Bay between New York City and Jersey City. It eventually drains into the Atlantic Ocean at New York Harbor (one of the largest natural harbors in the world).
The Hudson River flows through the eastern part of New York state and serves as a political boundary between the states of New Jersey and New York at its southern end. The lower half of the river is a tidal estuary, deeper than the body of water into which it flows, occupying the Hudson Fjord, an inlet which formed during the most recent period of North American glaciation, estimated at 26,000 to 13,300 years ago.